Peampring Chaimongkon, Sanohkan Sasiwimol
Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla 90110 Thailand.
J Indian Prosthodont Soc. 2014 Dec;14(4):376-80. doi: 10.1007/s13191-013-0335-x. Epub 2013 Dec 20.
To evaluate the durability of machinable dental restorative materials, this study performed an experiment to evaluate the flexural strength and Weibull statistics of a machinable lithium disilicate glass-ceramic and a machinable composite resin after being thermocycled for certain cycles. A total of 40 bar-shape specimens of were prepared with the dimension of 20 mm × 4 mm × 2 mm, which were divided into four groups of 10 specimens. Ten specimens of machinable lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent, Liechtenstein) and 10 specimens of machinable composite resin (Paradigm MZ 100, 3M ESPE, USA) were subjected to 3-point flexural strength test. Other 10 specimens of each material were thermocycled between water temperature of 5 and 55 °C for 10,000 cycles. After that, they were tested using 3-point flexural strength test. Statistical analysis was performed using two-way analysis of variance and Tukey multiple comparisons. Weibull analysis was performed to evaluate the reliability of the strength. Means of strength and their standard deviation were: thermocycled IPS e.max CAD 389.10 (50.75), non-thermocycled IPS e.max CAD 349.96 (38.34), thermocycled Paradigm MZ 100 157.51 (12.85), non-thermocycled Paradigm MZ 100 153.33 (19.97). Within each material group, there was no significant difference in flexural strength between thermocycled and non-thermocycled specimens. Considering the Weibull analysis, there was no statistical difference of Weibull modulus in all experimental groups. Within the limitation of this study, the results showed that there was no significant effect of themocycling on flexural strength and Weibull modulus of a machinable glass-ceramic and a machinable composite resin.
为评估可加工牙科修复材料的耐久性，本研究进行了一项实验，以评估一种可加工二硅酸锂玻璃陶瓷和一种可加工复合树脂在经过一定次数热循环后的弯曲强度和韦布尔统计量。共制备了40个尺寸为20 mm×4 mm×2 mm的条形试件，分为四组，每组10个试件。10个可加工二硅酸锂玻璃陶瓷试件（IPS e.max CAD，义获嘉伟瓦登特公司，列支敦士登）和10个可加工复合树脂试件（Paradigm MZ 100，3M ESPE公司，美国）进行三点弯曲强度测试。每种材料的另外10个试件在5至55°C的水温之间进行10000次热循环。之后，使用三点弯曲强度测试对其进行测试。采用双向方差分析和Tukey多重比较进行统计分析。进行韦布尔分析以评估强度的可靠性。强度均值及其标准差为：热循环后的IPS e.max CAD为389.10（50.75），未热循环的IPS e.max CAD为349.96（38.34），热循环后的Paradigm MZ 100为157.51（12.85），未热循环的Paradigm MZ 100为153.33（19.97）。在每个材料组中，热循环和未热循环的试件之间弯曲强度无显著差异。考虑韦布尔分析，所有实验组的韦布尔模量无统计学差异。在本研究的局限性内，结果表明热循环对可加工玻璃陶瓷和可加工复合树脂的弯曲强度和韦布尔模量没有显著影响。
